Biocidal trihydrocarbyltin salts

ABSTRACT

Trihydrocarbyltin salts of oxobenzothiazine acetic acids are used as biocides.

1/1969 Fish 1/1969 Fish FOREIGN PATENTS 1/1958 Belgium 2/1963 Germany...8/1964 Japan OTHER REFERENCES Lesbre et a1. Chem. Abst. V01. 52, Columns6165- 6166 (1958)QD1.A51

Primary Examiner-Natalie Trousof Atlorneys- Fritz G. Hochwald andChristen & Saboi ABSTRACT: Trihydrocarbyltin salts of oxobenzothiazineacetic acids are used as biocides.

BlOClDAL TRIHYDROCARBYLTIN SALTS This invention relates to novelbiocidal compositions which are useful against any kind ofmicro-organisms.

Organotin compounds containing one or more mercaptobenzothiazolategroups have already been proposed as biocides possessing fungicidal,bacterial, insecticidal, herbicidal and algicidal properties.

I have found organotin compounds which have a considerably higherbiocidal efficiency than said known compounds. The novel compounds aretriorganotin salts of oxobenzothiazine acetic acids and derivativesthereof.

The novel compounds have the formula R,R R=,SnOC-CH R wherein R R and Rare the same or different hydrocarbyl groups, e.g., alkyl, alkenyl,aralkyl, aralkenyl, cycloalkyl, cycloalkenyl, aryl, or aralkyl; R is anoxobenzothiazine radical on the ring of which one or two positions canbe substituted with an aliphatic or aromatic hydrocarbon rest;preferably, the compounds have the general formula s Iom-ooosmmm.

wherein R,, R and R are alkyl groups, having one to 12 carbon atoms andare usually the same.

The starting benzothiazine acetic acid compounds can be prepared bycondensation of the respective l,2-amino aryl thiols with maleic acid ormaleic anhydride, and said benzothiazine acetic acid compounds are thenpreferably reacted with an equimolar amount of a trihydrocarbyltin oxidein a suitable organic inert solvent such as hydrocarbon like, e.g.,hexane, cyclohexane, benzene, toluene, at temperatures in the range ofabout 20 to 200 C. When using a trihydrocarbyltin halide, the reactionmust be carried out in the presence of a l-lCl acceptor or with analkali salt of the oxobenzothiazine acetic acid.

The trihydrocarbyltin oxobenzothiazine acetates are mostly solid saltswhich are stable to oxidation in air and resistant to hydrolysis. Theyare soluble in most organic solvents and plasticizers and haveoutstanding biocidal activity. They may be used with or without aconventional carrier, and alone or in combination with other biocides,in form of dusts, sprays, or fumigating agents. They are particularlysuitable for incorporation in film-forming vehicles, paints, and thelike where they can be used, preferably in concentrations of about 0.05to percent, calculated on the vehicle, with advantage to treat cloth,leather, and wood against fungal and bacterial deterioration. Whenincorporated, e.g., in vinyl coatings, it may be sufi'icient to use amixture of bis (trihydrocarbyltin) oxide and the oxobenzothiazine aceticacid compound because these ingredients will form trihydrocarbyltin saltof the oxobenzothiazine acetic acid under the heat conditions em ployedin processing the vinyl compounds, e.g., poly (vinylchloride).

The following examples illustrate the preparation and the fungicidalproperties and the use of the novel compounds.

EXAMPLE 30 g. of 2-aminobenzenethiol were added slowly to 35 g. ofpulverized maleic acid. The exothermic reaction caused the mixture toset to a hard mass. After the completion of the reaction by heating toll0 C. for 15 minutes, the reaction product was cooled, broken up andrecrystallized in a 2:1 mix- Sn, calculated for C,,H, O,NSSn FoundEXAMPLE 2 Two brush coats of three paint formulations containing variouslevels of fungicide were successively applied uniformly to 1 square inch01 filter papers. After drying, the painted filter paper squares weredipped briefly in boiling water and placed on standard malt Agar platesseeded with an actively growing 7-day old culture of Pullulariapullulans The plates were then incubated at 28 C. for a period of 4weeks and observations were made weekly during the incubation period.

Three different paint formulations were used.

A. Polyvinyl Acetate Paint (PVA) of the composition Methyl Cellulose 2%0.9 lbs. Titanium Pigment L65 lbs. Magnesium Silicate 0.5l lbs. 325 MeshMica 0.30 lbs. Water l.2 lbs. Flexbound 800 (vinyl acetate-vinyl 2.35lbs. chloride copolymer;

53% solids) Wetting Agents, antifoaming agents, 0.3 lbs. freeze thawstabilizer B. Styrene-Butadiene Paint (S-B) of the composition TitaniumDioxide 1.6 lbs. Clay 0.5 lbs. Calcium Carbonate l.l lbs. MethylCellulose 2% L4 lbs. Water 0.95 lbs. Styrene-Butadiene emulsion (Dowlatex 2.l lbs. 307; 48% solids) Wetting agents, antifoarning agents.freeze thaw stabilizer 0.3 lbs.

C. Acrylic Paint (ACR) of the composition Titanium Pigment L05 lbs.Calcium Carbonate 2.25 lbs. Methyl Cellulose 2% 0.6l lbs. Water 0.96lbs. Acrylic Emulsion (Rhoplex AC 34; 2.43 lbs. 47% solids) WettingAgents, freeze thaw stabilizer 0.3 lbs.

antifoaming agents PVA 5-5 AC R Tribulyltindihydro-oxo- 0.1% 0.2% 0. l5b benzothiazine acetate Tributyltin mercapto- 0.1% 0.2% Failurebenzothiazole The table shows that the tributyltindihydro-oxobenzothiozine acetate had, in the PVA and 8-8 paints, thesame'biocidal effect as tributyltin mercaptobenzothiazole.

However, in the acrylic paint, where the latter compound wasineffective, the tributyltin dihydro-oxo-benzothiazine acetate waseffective already at the very low concentration of 0.1 percent.

EXAMPLE 3 A similar procedure was carried out using the same three paintsystems as employed in example 2 with a culture of Aspergillus oryzae ona mineral salts sucrose agar medium. After a period of incubation of 7days at 2830 C., the following minumum effective levels in the threepaint systems were as follows:

benzothiazole In all paint systems, the required effective amount of thetributyltin dihydro-oxo-benzothiazine acetate was at least 100 percentlower than that of the tributyltin mercapto benzothiazole.

EXAMPLE 4 A red iron oxide paint containing 140 g. of red iron oxide, 88g. of clay, 200 g. of zinc oxide, 400 g. of water white rosin solution(at 65 percent), 80 g. of coat tar, 80 g. of pure oil and 120 g. of highflash naphtha was applied to a cedar wood panel measuring 36 inches 6inches 1 inches and used as a standard. An identical panel was coatedwith the same paint containing 2 percent oftributyltin-2,3-dihydro-3-oxo-1,4- benzothiazine acetate and a thirdpanel was protected with 2 percent of tributyltin mercaptobenzothiazole.The panels were then immersed in a marine environment for 120 days(costal sea water, state of New Jersey).

After 60 days the unprotected panel showed considerable calcariousgrowth, some calcarious growth was observed on the panel treated withthe organotin mercaptobenzothiazole compound, whereas the panel coatedwith the paint containing tributyltin oxobenzothiazine acetate stillshowed complete protection. After days this trend increased and 50percent more bamacles had grown on the panel treated with the mercaptobenzothiazole.

After days the difference between the tributyltin mercapto benzothiazoleand the tributyltin oxobenzothiazine acetate was even greater and a hardslime covered 40 percent of the panel treated with the former compoundvs. 20 percent with the latter.

EXAMPLE 5 Tests for mildew resistance imparted by the fungicides of theinvention were carried out according to Federal Specification CCC-T-l9lb Method 5751.! May 6, 1953) as follows:

Solutions of respectively l0, 5, 4, 3, 2 and 1 percent of tributyltindihydro-oxo-benzothiazine acetate in methyl ethyl ketone were preparedand a piece of untreated cotton cloth was dipped in each solution forseveral minutes to deposit a sufficient quantity of fungicide. A pieceof the same cloth was left unprotected and used as a control. The testsamples were then air dried and placed with the control on a nutrientagar inoculated with the organism Chaetomium Globosum. During a 14-dayincubation at 30 C, the control failed after 7 days whereas the treatedsamples passed the l4-day test at all levels while inhibiting all fungusgrowth.

I claim:

1. An organotin compound having the formula wherein R,, R and R arealkyl of one to 12 carbon atoms.

2. The compound of claim 1 wherein R R and R are butyl.

t i i

2. The compound of claim 1 wherein R1, R2 and R3 are butyl.